With the development of electronic technologies, functions of display devices are on longer limited to receiving and displaying video signals. Nowadays, the display device has been integrated with a touch function, so that a control instruction can be input into the display device according to a touch operation performed by an operator on the display device.
Display devices of the related art integrated with a touch function are divided into an add-on touch screen, an on-cell touch screen and an in-cell touch screen according to structures of the display devices. However, in any of the existing touch screens with the above various structures, touch signal lines connecting with touch electrodes are necessary. In touch display devices of existing technology, one gate line is used by each row of pixels and one data line is used by each column of pixels. In addition, a single metallic layer is also required for preparing touch lines so as to connect with touch driving electrodes corresponding to the touch lines for providing touch driving signals. Thus, a process for fabricating touch lines is additionally added, thereby leading to an increasing production cost for the touch display device.